Consider the general reaction given below at 400 K

$$xA(g)\rightleftharpoons yB(g).$$

The values of $K_p$ and $K_c$ are studied under the same condition of temperature but variation in $x$ and $y$.

(i) $K_p=85.87$ and $K_c=2.586$ appropriate units

(ii) $K_p=0.862$ and $K_c=28.62$ appropriate units

The values of $x$ and $y$ in (i) and (ii) respectively are :

Question

Consider the general reaction given below at 400 K

$$xA(g)\rightleftharpoons yB(g).$$

The values of $K_p$ and $K_c$ are studied under the same condition of temperature but variation in $x$ and $y$.

(i) $K_p=85.87$ and $K_c=2.586$ appropriate units

(ii) $K_p=0.862$ and $K_c=28.62$ appropriate units

The values of $x$ and $y$ in (i) and (ii) respectively are :

Accepted Answer

A. 1. Use the relation between $K_p$ and $K_c$, which depends on the change in gas moles $\Delta n_g = y-x$, so first determine the sign of $\Delta n_g$ for case (i). Given $K_p>K_c$ in case (i), and $K_p=K_c(RT)^{\Delta n_g}$, this requires $\Delta n_g>0$ (positive exponent increases the value when $RT>1$). 2. Solve for $\Delta n_g$ numerically using the given values and $RT=0.0821 imes400\approx32.84$. Given $85.87=2.586 imes(32.84)^{\Delta n_g}$, solving gives $\Delta n_g\approx1$, so $y-x=1$. 3. Choose the simplest whole numbers satisfying $y=x+1$: take $x=1,y=2$. 4. For case (ii), $K_p